Question: What is the greatest common factor of $24$ and $40$ ? Another way to say this is: $\operatorname{gcf}(24, 40) = {?}$
Answer: The greatest common factor is the largest number that is a factor of both $24$ and $40$ The factors of $24$ are $1$ $2$ $3$ $4$ $6$ $8$ $12$ , and $24$ The factors of $40$ are $1$ $2$ $4$ $5$ $8$ $10$ $20$ , and $40$ Thus, the greatest common factor of $24$ and $40$ is $8$. $\operatorname{gcf}(24, 40) = 8$